North Korean hackers have stepped up their attacks on U.S. defense contractors in an apparent effort to gain intelligence on weapon systems and other assets that might be used against the country in an armed conflict with the United States and its allies, The Security Ledger has learned.

The NotPetya malware infection shut down pharmaceutical giant Merck’s production of the pediatric vaccine GARDASIL last June, forcing the company to borrow the drug from a stockpile maintained by the U.S. Centers for Disease Control and Prevention to meet demand.

In this 67th episode of The Security Ledger Podcast, we talk with Bob Rudis of the firm Rapid7 about KRACK, a security hole that affects most wi-fi hotspots. Also: Or Katz of Akamai talks about that company’s work analyzing fast-flux botnets, which have become like AirBnB for cyber criminals looking for a place to host malicious networks. Finally: Tim Jarrett of Veracode tells us how a single security hole in an open source library found its way into millions of applications.